State the body location in which macrophages originate.
Describe how a macrophage works.
M. tuberculosis can sometimes survive inside macrophages. Suggest one way M. tuberculosis may survive within a macrophage.
A healthy person has additional defence mechanisms in the gas-exchange system that stop bacteria entering cells. Describe these defences and explain how bacteria in inhaled air are prevented from entering gas-exchange cells.
In people with a weakened immune system, Mycobacterium tuberculosis can infect other organs and tissues, including the kidneys and joints. Suggest how the bacteria may spread from the lungs to other organs.
In humans, TB can also be caused by another species of bacterium, Mycobacterium bovis. State the mode of transmission of this pathogen to humans.
The standard treatment for TB lasts six months and begins with four different antibiotics. If no antibiotic resistance is found, the treatment is cut down to two of the four antibiotics. The two antibiotics used are rifampicin and isoniazid. Suggest the benefits of starting treatment with four different antibiotics.
State the patterns shown in Table 2.1.
TB has major global significance. Discuss the factors that influence the trends shown in Table 2.1.